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IP subnet calculator

Type an address with its prefix or mask to see the network, its usable range and masks. Split it into smaller subnets, or look up any prefix in the reference tables.

Network74.99.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
74.99.0.0
Broadcast address
74.99.127.255
First usable
74.99.0.1
Last usable
74.99.127.254
Usable hosts
32,766 (32,768 less the network and broadcast addresses)
Subnet mask
255.255.128.0
Wildcard mask
0.0.127.255 (Cisco ACLs, OSPF)
Prefix length
/17
Type
Public public
Old class
A (default /8)
As numbers
Hex 4A630000 · Integer 1248002048 to 1248034815
Reverse DNS zones
0.99.74.in-addr.arpa
1.99.74.in-addr.arpa
2.99.74.in-addr.arpa
3.99.74.in-addr.arpa
4.99.74.in-addr.arpa
5.99.74.in-addr.arpa
6.99.74.in-addr.arpa
7.99.74.in-addr.arpa
8.99.74.in-addr.arpa
9.99.74.in-addr.arpa
10.99.74.in-addr.arpa
11.99.74.in-addr.arpa
12.99.74.in-addr.arpa
13.99.74.in-addr.arpa
14.99.74.in-addr.arpa
15.99.74.in-addr.arpa
and 112 more
/17 is not on a 8-bit boundary, so it takes 128 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01001010.01100011.00000000.0000000074.99.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network01001010.01100011.00000000.0000000074.99.0.0
Broadcast01001010.01100011.01111111.1111111174.99.127.255
Split into smaller subnets/28
/18 (2)/19 (4)/20 (8)/21 (16)/22 (32)/23 (64)/24 (128)/25 (256)/26 (512)/27 (1,024)/28 (2,048)/29 (4,096)

74.99.0.0/17 makes 2,048 subnets of /28; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
174.99.0.0/2874.99.0.1 to 74.99.0.1474.99.0.1514
274.99.0.16/2874.99.0.17 to 74.99.0.3074.99.0.3114
374.99.0.32/2874.99.0.33 to 74.99.0.4674.99.0.4714
474.99.0.48/2874.99.0.49 to 74.99.0.6274.99.0.6314
574.99.0.64/2874.99.0.65 to 74.99.0.7874.99.0.7914
674.99.0.80/2874.99.0.81 to 74.99.0.9474.99.0.9514
774.99.0.96/2874.99.0.97 to 74.99.0.11074.99.0.11114
874.99.0.112/2874.99.0.113 to 74.99.0.12674.99.0.12714
974.99.0.128/2874.99.0.129 to 74.99.0.14274.99.0.14314
1074.99.0.144/2874.99.0.145 to 74.99.0.15874.99.0.15914
1174.99.0.160/2874.99.0.161 to 74.99.0.17474.99.0.17514
1274.99.0.176/2874.99.0.177 to 74.99.0.19074.99.0.19114
1374.99.0.192/2874.99.0.193 to 74.99.0.20674.99.0.20714
1474.99.0.208/2874.99.0.209 to 74.99.0.22274.99.0.22314
1574.99.0.224/2874.99.0.225 to 74.99.0.23874.99.0.23914
1674.99.0.240/2874.99.0.241 to 74.99.0.25474.99.0.25514
1774.99.1.0/2874.99.1.1 to 74.99.1.1474.99.1.1514
1874.99.1.16/2874.99.1.17 to 74.99.1.3074.99.1.3114
1974.99.1.32/2874.99.1.33 to 74.99.1.4674.99.1.4714
2074.99.1.48/2874.99.1.49 to 74.99.1.6274.99.1.6314
2174.99.1.64/2874.99.1.65 to 74.99.1.7874.99.1.7914
2274.99.1.80/2874.99.1.81 to 74.99.1.9474.99.1.9514
2374.99.1.96/2874.99.1.97 to 74.99.1.11074.99.1.11114
2474.99.1.112/2874.99.1.113 to 74.99.1.12674.99.1.12714
2574.99.1.128/2874.99.1.129 to 74.99.1.14274.99.1.14314
2674.99.1.144/2874.99.1.145 to 74.99.1.15874.99.1.15914
2774.99.1.160/2874.99.1.161 to 74.99.1.17474.99.1.17514
2874.99.1.176/2874.99.1.177 to 74.99.1.19074.99.1.19114
2974.99.1.192/2874.99.1.193 to 74.99.1.20674.99.1.20714
3074.99.1.208/2874.99.1.209 to 74.99.1.22274.99.1.22314
3174.99.1.224/2874.99.1.225 to 74.99.1.23874.99.1.23914
3274.99.1.240/2874.99.1.241 to 74.99.1.25474.99.1.25514
3374.99.2.0/2874.99.2.1 to 74.99.2.1474.99.2.1514
3474.99.2.16/2874.99.2.17 to 74.99.2.3074.99.2.3114
3574.99.2.32/2874.99.2.33 to 74.99.2.4674.99.2.4714
3674.99.2.48/2874.99.2.49 to 74.99.2.6274.99.2.6314
3774.99.2.64/2874.99.2.65 to 74.99.2.7874.99.2.7914
3874.99.2.80/2874.99.2.81 to 74.99.2.9474.99.2.9514
3974.99.2.96/2874.99.2.97 to 74.99.2.11074.99.2.11114
4074.99.2.112/2874.99.2.113 to 74.99.2.12674.99.2.12714
4174.99.2.128/2874.99.2.129 to 74.99.2.14274.99.2.14314
4274.99.2.144/2874.99.2.145 to 74.99.2.15874.99.2.15914
4374.99.2.160/2874.99.2.161 to 74.99.2.17474.99.2.17514
4474.99.2.176/2874.99.2.177 to 74.99.2.19074.99.2.19114
4574.99.2.192/2874.99.2.193 to 74.99.2.20674.99.2.20714
4674.99.2.208/2874.99.2.209 to 74.99.2.22274.99.2.22314
4774.99.2.224/2874.99.2.225 to 74.99.2.23874.99.2.23914
4874.99.2.240/2874.99.2.241 to 74.99.2.25474.99.2.25514
4974.99.3.0/2874.99.3.1 to 74.99.3.1474.99.3.1514
5074.99.3.16/2874.99.3.17 to 74.99.3.3074.99.3.3114
5174.99.3.32/2874.99.3.33 to 74.99.3.4674.99.3.4714
5274.99.3.48/2874.99.3.49 to 74.99.3.6274.99.3.6314
5374.99.3.64/2874.99.3.65 to 74.99.3.7874.99.3.7914
5474.99.3.80/2874.99.3.81 to 74.99.3.9474.99.3.9514
5574.99.3.96/2874.99.3.97 to 74.99.3.11074.99.3.11114
5674.99.3.112/2874.99.3.113 to 74.99.3.12674.99.3.12714
5774.99.3.128/2874.99.3.129 to 74.99.3.14274.99.3.14314
5874.99.3.144/2874.99.3.145 to 74.99.3.15874.99.3.15914
5974.99.3.160/2874.99.3.161 to 74.99.3.17474.99.3.17514
6074.99.3.176/2874.99.3.177 to 74.99.3.19074.99.3.19114
6174.99.3.192/2874.99.3.193 to 74.99.3.20674.99.3.20714
6274.99.3.208/2874.99.3.209 to 74.99.3.22274.99.3.22314
6374.99.3.224/2874.99.3.225 to 74.99.3.23874.99.3.23914
6474.99.3.240/2874.99.3.241 to 74.99.3.25474.99.3.25514
6574.99.4.0/2874.99.4.1 to 74.99.4.1474.99.4.1514
6674.99.4.16/2874.99.4.17 to 74.99.4.3074.99.4.3114
6774.99.4.32/2874.99.4.33 to 74.99.4.4674.99.4.4714
6874.99.4.48/2874.99.4.49 to 74.99.4.6274.99.4.6314
6974.99.4.64/2874.99.4.65 to 74.99.4.7874.99.4.7914
7074.99.4.80/2874.99.4.81 to 74.99.4.9474.99.4.9514
7174.99.4.96/2874.99.4.97 to 74.99.4.11074.99.4.11114
7274.99.4.112/2874.99.4.113 to 74.99.4.12674.99.4.12714
7374.99.4.128/2874.99.4.129 to 74.99.4.14274.99.4.14314
7474.99.4.144/2874.99.4.145 to 74.99.4.15874.99.4.15914
7574.99.4.160/2874.99.4.161 to 74.99.4.17474.99.4.17514
7674.99.4.176/2874.99.4.177 to 74.99.4.19074.99.4.19114
7774.99.4.192/2874.99.4.193 to 74.99.4.20674.99.4.20714
7874.99.4.208/2874.99.4.209 to 74.99.4.22274.99.4.22314
7974.99.4.224/2874.99.4.225 to 74.99.4.23874.99.4.23914
8074.99.4.240/2874.99.4.241 to 74.99.4.25474.99.4.25514
8174.99.5.0/2874.99.5.1 to 74.99.5.1474.99.5.1514
8274.99.5.16/2874.99.5.17 to 74.99.5.3074.99.5.3114
8374.99.5.32/2874.99.5.33 to 74.99.5.4674.99.5.4714
8474.99.5.48/2874.99.5.49 to 74.99.5.6274.99.5.6314
8574.99.5.64/2874.99.5.65 to 74.99.5.7874.99.5.7914
8674.99.5.80/2874.99.5.81 to 74.99.5.9474.99.5.9514
8774.99.5.96/2874.99.5.97 to 74.99.5.11074.99.5.11114
8874.99.5.112/2874.99.5.113 to 74.99.5.12674.99.5.12714
8974.99.5.128/2874.99.5.129 to 74.99.5.14274.99.5.14314
9074.99.5.144/2874.99.5.145 to 74.99.5.15874.99.5.15914
9174.99.5.160/2874.99.5.161 to 74.99.5.17474.99.5.17514
9274.99.5.176/2874.99.5.177 to 74.99.5.19074.99.5.19114
9374.99.5.192/2874.99.5.193 to 74.99.5.20674.99.5.20714
9474.99.5.208/2874.99.5.209 to 74.99.5.22274.99.5.22314
9574.99.5.224/2874.99.5.225 to 74.99.5.23874.99.5.23914
9674.99.5.240/2874.99.5.241 to 74.99.5.25474.99.5.25514
9774.99.6.0/2874.99.6.1 to 74.99.6.1474.99.6.1514
9874.99.6.16/2874.99.6.17 to 74.99.6.3074.99.6.3114
9974.99.6.32/2874.99.6.33 to 74.99.6.4674.99.6.4714
10074.99.6.48/2874.99.6.49 to 74.99.6.6274.99.6.6314
10174.99.6.64/2874.99.6.65 to 74.99.6.7874.99.6.7914
10274.99.6.80/2874.99.6.81 to 74.99.6.9474.99.6.9514
10374.99.6.96/2874.99.6.97 to 74.99.6.11074.99.6.11114
10474.99.6.112/2874.99.6.113 to 74.99.6.12674.99.6.12714
10574.99.6.128/2874.99.6.129 to 74.99.6.14274.99.6.14314
10674.99.6.144/2874.99.6.145 to 74.99.6.15874.99.6.15914
10774.99.6.160/2874.99.6.161 to 74.99.6.17474.99.6.17514
10874.99.6.176/2874.99.6.177 to 74.99.6.19074.99.6.19114
10974.99.6.192/2874.99.6.193 to 74.99.6.20674.99.6.20714
11074.99.6.208/2874.99.6.209 to 74.99.6.22274.99.6.22314
11174.99.6.224/2874.99.6.225 to 74.99.6.23874.99.6.23914
11274.99.6.240/2874.99.6.241 to 74.99.6.25474.99.6.25514
11374.99.7.0/2874.99.7.1 to 74.99.7.1474.99.7.1514
11474.99.7.16/2874.99.7.17 to 74.99.7.3074.99.7.3114
11574.99.7.32/2874.99.7.33 to 74.99.7.4674.99.7.4714
11674.99.7.48/2874.99.7.49 to 74.99.7.6274.99.7.6314
11774.99.7.64/2874.99.7.65 to 74.99.7.7874.99.7.7914
11874.99.7.80/2874.99.7.81 to 74.99.7.9474.99.7.9514
11974.99.7.96/2874.99.7.97 to 74.99.7.11074.99.7.11114
12074.99.7.112/2874.99.7.113 to 74.99.7.12674.99.7.12714
12174.99.7.128/2874.99.7.129 to 74.99.7.14274.99.7.14314
12274.99.7.144/2874.99.7.145 to 74.99.7.15874.99.7.15914
12374.99.7.160/2874.99.7.161 to 74.99.7.17474.99.7.17514
12474.99.7.176/2874.99.7.177 to 74.99.7.19074.99.7.19114
12574.99.7.192/2874.99.7.193 to 74.99.7.20674.99.7.20714
12674.99.7.208/2874.99.7.209 to 74.99.7.22274.99.7.22314
12774.99.7.224/2874.99.7.225 to 74.99.7.23874.99.7.23914
12874.99.7.240/2874.99.7.241 to 74.99.7.25474.99.7.25514
12974.99.8.0/2874.99.8.1 to 74.99.8.1474.99.8.1514
13074.99.8.16/2874.99.8.17 to 74.99.8.3074.99.8.3114
13174.99.8.32/2874.99.8.33 to 74.99.8.4674.99.8.4714
13274.99.8.48/2874.99.8.49 to 74.99.8.6274.99.8.6314
13374.99.8.64/2874.99.8.65 to 74.99.8.7874.99.8.7914
13474.99.8.80/2874.99.8.81 to 74.99.8.9474.99.8.9514
13574.99.8.96/2874.99.8.97 to 74.99.8.11074.99.8.11114
13674.99.8.112/2874.99.8.113 to 74.99.8.12674.99.8.12714
13774.99.8.128/2874.99.8.129 to 74.99.8.14274.99.8.14314
13874.99.8.144/2874.99.8.145 to 74.99.8.15874.99.8.15914
13974.99.8.160/2874.99.8.161 to 74.99.8.17474.99.8.17514
14074.99.8.176/2874.99.8.177 to 74.99.8.19074.99.8.19114
14174.99.8.192/2874.99.8.193 to 74.99.8.20674.99.8.20714
14274.99.8.208/2874.99.8.209 to 74.99.8.22274.99.8.22314
14374.99.8.224/2874.99.8.225 to 74.99.8.23874.99.8.23914
14474.99.8.240/2874.99.8.241 to 74.99.8.25474.99.8.25514
14574.99.9.0/2874.99.9.1 to 74.99.9.1474.99.9.1514
14674.99.9.16/2874.99.9.17 to 74.99.9.3074.99.9.3114
14774.99.9.32/2874.99.9.33 to 74.99.9.4674.99.9.4714
14874.99.9.48/2874.99.9.49 to 74.99.9.6274.99.9.6314
14974.99.9.64/2874.99.9.65 to 74.99.9.7874.99.9.7914
15074.99.9.80/2874.99.9.81 to 74.99.9.9474.99.9.9514
15174.99.9.96/2874.99.9.97 to 74.99.9.11074.99.9.11114
15274.99.9.112/2874.99.9.113 to 74.99.9.12674.99.9.12714
15374.99.9.128/2874.99.9.129 to 74.99.9.14274.99.9.14314
15474.99.9.144/2874.99.9.145 to 74.99.9.15874.99.9.15914
15574.99.9.160/2874.99.9.161 to 74.99.9.17474.99.9.17514
15674.99.9.176/2874.99.9.177 to 74.99.9.19074.99.9.19114
15774.99.9.192/2874.99.9.193 to 74.99.9.20674.99.9.20714
15874.99.9.208/2874.99.9.209 to 74.99.9.22274.99.9.22314
15974.99.9.224/2874.99.9.225 to 74.99.9.23874.99.9.23914
16074.99.9.240/2874.99.9.241 to 74.99.9.25474.99.9.25514
16174.99.10.0/2874.99.10.1 to 74.99.10.1474.99.10.1514
16274.99.10.16/2874.99.10.17 to 74.99.10.3074.99.10.3114
16374.99.10.32/2874.99.10.33 to 74.99.10.4674.99.10.4714
16474.99.10.48/2874.99.10.49 to 74.99.10.6274.99.10.6314
16574.99.10.64/2874.99.10.65 to 74.99.10.7874.99.10.7914
16674.99.10.80/2874.99.10.81 to 74.99.10.9474.99.10.9514
16774.99.10.96/2874.99.10.97 to 74.99.10.11074.99.10.11114
16874.99.10.112/2874.99.10.113 to 74.99.10.12674.99.10.12714
16974.99.10.128/2874.99.10.129 to 74.99.10.14274.99.10.14314
17074.99.10.144/2874.99.10.145 to 74.99.10.15874.99.10.15914
17174.99.10.160/2874.99.10.161 to 74.99.10.17474.99.10.17514
17274.99.10.176/2874.99.10.177 to 74.99.10.19074.99.10.19114
17374.99.10.192/2874.99.10.193 to 74.99.10.20674.99.10.20714
17474.99.10.208/2874.99.10.209 to 74.99.10.22274.99.10.22314
17574.99.10.224/2874.99.10.225 to 74.99.10.23874.99.10.23914
17674.99.10.240/2874.99.10.241 to 74.99.10.25474.99.10.25514
17774.99.11.0/2874.99.11.1 to 74.99.11.1474.99.11.1514
17874.99.11.16/2874.99.11.17 to 74.99.11.3074.99.11.3114
17974.99.11.32/2874.99.11.33 to 74.99.11.4674.99.11.4714
18074.99.11.48/2874.99.11.49 to 74.99.11.6274.99.11.6314
18174.99.11.64/2874.99.11.65 to 74.99.11.7874.99.11.7914
18274.99.11.80/2874.99.11.81 to 74.99.11.9474.99.11.9514
18374.99.11.96/2874.99.11.97 to 74.99.11.11074.99.11.11114
18474.99.11.112/2874.99.11.113 to 74.99.11.12674.99.11.12714
18574.99.11.128/2874.99.11.129 to 74.99.11.14274.99.11.14314
18674.99.11.144/2874.99.11.145 to 74.99.11.15874.99.11.15914
18774.99.11.160/2874.99.11.161 to 74.99.11.17474.99.11.17514
18874.99.11.176/2874.99.11.177 to 74.99.11.19074.99.11.19114
18974.99.11.192/2874.99.11.193 to 74.99.11.20674.99.11.20714
19074.99.11.208/2874.99.11.209 to 74.99.11.22274.99.11.22314
19174.99.11.224/2874.99.11.225 to 74.99.11.23874.99.11.23914
19274.99.11.240/2874.99.11.241 to 74.99.11.25474.99.11.25514
19374.99.12.0/2874.99.12.1 to 74.99.12.1474.99.12.1514
19474.99.12.16/2874.99.12.17 to 74.99.12.3074.99.12.3114
19574.99.12.32/2874.99.12.33 to 74.99.12.4674.99.12.4714
19674.99.12.48/2874.99.12.49 to 74.99.12.6274.99.12.6314
19774.99.12.64/2874.99.12.65 to 74.99.12.7874.99.12.7914
19874.99.12.80/2874.99.12.81 to 74.99.12.9474.99.12.9514
19974.99.12.96/2874.99.12.97 to 74.99.12.11074.99.12.11114
20074.99.12.112/2874.99.12.113 to 74.99.12.12674.99.12.12714
20174.99.12.128/2874.99.12.129 to 74.99.12.14274.99.12.14314
20274.99.12.144/2874.99.12.145 to 74.99.12.15874.99.12.15914
20374.99.12.160/2874.99.12.161 to 74.99.12.17474.99.12.17514
20474.99.12.176/2874.99.12.177 to 74.99.12.19074.99.12.19114
20574.99.12.192/2874.99.12.193 to 74.99.12.20674.99.12.20714
20674.99.12.208/2874.99.12.209 to 74.99.12.22274.99.12.22314
20774.99.12.224/2874.99.12.225 to 74.99.12.23874.99.12.23914
20874.99.12.240/2874.99.12.241 to 74.99.12.25474.99.12.25514
20974.99.13.0/2874.99.13.1 to 74.99.13.1474.99.13.1514
21074.99.13.16/2874.99.13.17 to 74.99.13.3074.99.13.3114
21174.99.13.32/2874.99.13.33 to 74.99.13.4674.99.13.4714
21274.99.13.48/2874.99.13.49 to 74.99.13.6274.99.13.6314
21374.99.13.64/2874.99.13.65 to 74.99.13.7874.99.13.7914
21474.99.13.80/2874.99.13.81 to 74.99.13.9474.99.13.9514
21574.99.13.96/2874.99.13.97 to 74.99.13.11074.99.13.11114
21674.99.13.112/2874.99.13.113 to 74.99.13.12674.99.13.12714
21774.99.13.128/2874.99.13.129 to 74.99.13.14274.99.13.14314
21874.99.13.144/2874.99.13.145 to 74.99.13.15874.99.13.15914
21974.99.13.160/2874.99.13.161 to 74.99.13.17474.99.13.17514
22074.99.13.176/2874.99.13.177 to 74.99.13.19074.99.13.19114
22174.99.13.192/2874.99.13.193 to 74.99.13.20674.99.13.20714
22274.99.13.208/2874.99.13.209 to 74.99.13.22274.99.13.22314
22374.99.13.224/2874.99.13.225 to 74.99.13.23874.99.13.23914
22474.99.13.240/2874.99.13.241 to 74.99.13.25474.99.13.25514
22574.99.14.0/2874.99.14.1 to 74.99.14.1474.99.14.1514
22674.99.14.16/2874.99.14.17 to 74.99.14.3074.99.14.3114
22774.99.14.32/2874.99.14.33 to 74.99.14.4674.99.14.4714
22874.99.14.48/2874.99.14.49 to 74.99.14.6274.99.14.6314
22974.99.14.64/2874.99.14.65 to 74.99.14.7874.99.14.7914
23074.99.14.80/2874.99.14.81 to 74.99.14.9474.99.14.9514
23174.99.14.96/2874.99.14.97 to 74.99.14.11074.99.14.11114
23274.99.14.112/2874.99.14.113 to 74.99.14.12674.99.14.12714
23374.99.14.128/2874.99.14.129 to 74.99.14.14274.99.14.14314
23474.99.14.144/2874.99.14.145 to 74.99.14.15874.99.14.15914
23574.99.14.160/2874.99.14.161 to 74.99.14.17474.99.14.17514
23674.99.14.176/2874.99.14.177 to 74.99.14.19074.99.14.19114
23774.99.14.192/2874.99.14.193 to 74.99.14.20674.99.14.20714
23874.99.14.208/2874.99.14.209 to 74.99.14.22274.99.14.22314
23974.99.14.224/2874.99.14.225 to 74.99.14.23874.99.14.23914
24074.99.14.240/2874.99.14.241 to 74.99.14.25474.99.14.25514
24174.99.15.0/2874.99.15.1 to 74.99.15.1474.99.15.1514
24274.99.15.16/2874.99.15.17 to 74.99.15.3074.99.15.3114
24374.99.15.32/2874.99.15.33 to 74.99.15.4674.99.15.4714
24474.99.15.48/2874.99.15.49 to 74.99.15.6274.99.15.6314
24574.99.15.64/2874.99.15.65 to 74.99.15.7874.99.15.7914
24674.99.15.80/2874.99.15.81 to 74.99.15.9474.99.15.9514
24774.99.15.96/2874.99.15.97 to 74.99.15.11074.99.15.11114
24874.99.15.112/2874.99.15.113 to 74.99.15.12674.99.15.12714
24974.99.15.128/2874.99.15.129 to 74.99.15.14274.99.15.14314
25074.99.15.144/2874.99.15.145 to 74.99.15.15874.99.15.15914
25174.99.15.160/2874.99.15.161 to 74.99.15.17474.99.15.17514
25274.99.15.176/2874.99.15.177 to 74.99.15.19074.99.15.19114
25374.99.15.192/2874.99.15.193 to 74.99.15.20674.99.15.20714
25474.99.15.208/2874.99.15.209 to 74.99.15.22274.99.15.22314
25574.99.15.224/2874.99.15.225 to 74.99.15.23874.99.15.23914
25674.99.15.240/2874.99.15.241 to 74.99.15.25474.99.15.25514

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
PrefixSubnet maskWildcardAddressesUsable hostsSizeTypical use
/00.0.0.0255.255.255.2554,294,967,2964,294,967,29416,777,216 × /24
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,6468,388,608 × /24
/2192.0.0.063.255.255.2551,073,741,8241,073,741,8224,194,304 × /24
/3224.0.0.031.255.255.255536,870,912536,870,9102,097,152 × /24
/4240.0.0.015.255.255.255268,435,456268,435,4541,048,576 × /24
/5248.0.0.07.255.255.255134,217,728134,217,726524,288 × /24
/6252.0.0.03.255.255.25567,108,86467,108,862262,144 × /24
/7254.0.0.01.255.255.25533,554,43233,554,430131,072 × /24
/8255.0.0.00.255.255.25516,777,21616,777,21465,536 × /24Old class A; 10.0.0.0/8
/9255.128.0.00.127.255.2558,388,6088,388,60632,768 × /24
/10255.192.0.00.63.255.2554,194,3044,194,30216,384 × /24
/11255.224.0.00.31.255.2552,097,1522,097,1508,192 × /24
/12255.240.0.00.15.255.2551,048,5761,048,5744,096 × /24172.16.0.0/12
/13255.248.0.00.7.255.255524,288524,2862,048 × /24
/14255.252.0.00.3.255.255262,144262,1421,024 × /24
/15255.254.0.00.1.255.255131,072131,070512 × /24
/16255.255.0.00.0.255.25565,53665,534256 × /24Old class B; 192.168.0.0/16
/17255.255.128.00.0.127.25532,76832,766128 × /24
/18255.255.192.00.0.63.25516,38416,38264 × /24
/19255.255.224.00.0.31.2558,1928,19032 × /24
/20255.255.240.00.0.15.2554,0964,09416 × /24
/21255.255.248.00.0.7.2552,0482,0468 × /24
/22255.255.252.00.0.3.2551,0241,0224 × /24Large office or guest Wi-Fi (1,022 hosts)
/23255.255.254.00.0.1.2555125102 × /24Larger office LAN (510 hosts)
/24255.255.255.00.0.0.2552562541 × /24Typical office LAN (old class C)
/25255.255.255.1280.0.0.1271281261/2 of a /24Smaller LAN or VLAN
/26255.255.255.1920.0.0.6364621/4 of a /24Smaller LAN or VLAN
/27255.255.255.2240.0.0.3132301/8 of a /24Small VLAN, phones, cameras
/28255.255.255.2400.0.0.1516141/16 of a /24Small VLAN, phones, cameras
/29255.255.255.2480.0.0.7861/32 of a /24Small fixed public block (5 usable)
/30255.255.255.2520.0.0.3421/64 of a /24Point-to-point (old style)
/31255.255.255.2540.0.0.1221/128 of a /24Point-to-point link (RFC 3021)
/32255.255.255.2550.0.0.0111/256 of a /24One host

IPv6 prefix reference

IPv6 prefix lengths
PrefixAddresses/64 LANs/48 sitesNibbleTypical use
/342,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)2,305,843,009,213,693,95235,184,372,088,832NoAll global unicast (2000::/3)
/165,192,296,858,534,827,628,530,496,329,220,096 (2^112)281,474,976,710,6564,294,967,296Yes
/20324,518,553,658,426,726,783,156,020,576,256 (2^108)17,592,186,044,416268,435,456YesLarge provider allocation (RIPE minimum for some)
/29633,825,300,114,114,700,748,351,602,688 (2^99)34,359,738,368524,288NoRIPE allocation to a provider (often)
/3279,228,162,514,264,337,593,543,950,336 (2^96)4,294,967,29665,536YesProvider allocation (RIPE default)
/364,951,760,157,141,521,099,596,496,896 (2^92)268,435,4564,096Yes
/40309,485,009,821,345,068,724,781,056 (2^88)16,777,216256Yes
/4419,342,813,113,834,066,795,298,816 (2^84)1,048,57616Yes
/481,208,925,819,614,629,174,706,176 (2^80)65,5361YesOne site or organisation (RIPE PI / assignment)
/5275,557,863,725,914,323,419,136 (2^76)4,096Yes
/564,722,366,482,869,645,213,696 (2^72)256YesSmall site or home (common provider assignment)
/60295,147,905,179,352,825,856 (2^68)16YesSome home broadband (16 LANs)
/6418,446,744,073,709,551,616 (2^64)1YesOne LAN or VLAN (needed for SLAAC)
/7272,057,594,037,927,936 (2^56)1/256 of a /64Yes
/80281,474,976,710,656 (2^48)1/65,536 of a /64Yes
/964,294,967,2961/4,294,967,296 of a /64YesEmbeds an IPv4 address (NAT64)
/11265,5361/281,474,976,710,656 of a /64Yes
/1202561/72,057,594,037,927,936 of a /64Yes
/124161/1,152,921,504,606,846,976 of a /64Yes
/12641/4,611,686,018,427,387,904 of a /64No
/12721/9,223,372,036,854,775,808 of a /64NoPoint-to-point link (RFC 6164)
/12811/18,446,744,073,709,551,616 of a /64YesOne host or loopback

Private and special ranges

IPv4

Special-purpose ranges
RangeNameWhat it is
255.255.255.255/32Limited broadcastEvery host on the local network
0.0.0.0/8This networkNot routed; 0.0.0.0 means "any address" in settings
10.0.0.0/8Private (RFC 1918)Office and home networks; not routed on the internet
100.64.0.0/10Shared address space (CGNAT)Used by providers behind carrier-grade NAT (RFC 6598)
127.0.0.0/8LoopbackThis computer
169.254.0.0/16Link-local (APIPA)Self-assigned when no DHCP server answers
172.16.0.0/12Private (RFC 1918)Office and home networks; not routed on the internet
192.0.0.0/24IETF protocol assignmentsSpecial uses such as DS-Lite
192.0.2.0/24Documentation (TEST-NET-1)For examples; never used on a network
192.88.99.0/246to4 relay (deprecated)Formerly anycast for 6to4
192.168.0.0/16Private (RFC 1918)Office and home networks; not routed on the internet
198.18.0.0/15BenchmarkingNetwork equipment testing (RFC 2544)
198.51.100.0/24Documentation (TEST-NET-2)For examples; never used on a network
203.0.113.0/24Documentation (TEST-NET-3)For examples; never used on a network
224.0.0.0/4MulticastOne-to-many traffic, such as IPTV and routing protocols
240.0.0.0/4ReservedFuture use; not usable on most systems

IPv6

Special-purpose ranges
RangeNameWhat it is
::/128UnspecifiedNo address; :: means "any address" in settings
::1/128LoopbackThis computer
::ffff:0:0/96IPv4-mappedAn IPv4 address written as IPv6
64:ff9b::/96NAT64IPv4 addresses reached through a NAT64 gateway
100::/64Discard onlyTraffic sent here is dropped (RFC 6666)
2001:db8::/32DocumentationFor examples; never used on a network
2001::/32TeredoIPv6 tunnelled over IPv4 UDP
2002::/166to4IPv6 tunnelled over IPv4 (largely retired)
3fff::/20DocumentationFor examples (RFC 9637)
fc00::/7Unique local (ULA)Private IPv6, like RFC 1918; usually fd00::/8
fe80::/10Link-localEvery IPv6 interface has one; not routed
ff00::/8MulticastOne-to-many traffic; replaces broadcast
2000::/3Global unicastPublic internet addresses

About this tool

A network is written as an address and a prefix length, such as 192.168.1.0/24: the first 24 bits name the network and the rest number the devices on it. The calculator works out where the network starts and ends, how many devices it holds, its subnet and wildcard masks, and the reverse DNS zone to ask your provider for.

It also splits a network into equal smaller ones (one per VLAN or site), turns a range of addresses into the fewest CIDR blocks for a firewall rule, and lists every IPv4 prefix length and the common IPv6 ones in reference tables.

Common questions

Why are two addresses lost in every IPv4 subnet?

The first address names the network and the last is the broadcast address, so a /24 has 256 addresses but 254 for devices. A /31 (a link between two routers) and a /32 (one host) are the exceptions.

What size of IPv6 network should a LAN use?

Always /64. Devices pick their own address within it (SLAAC), which needs the full 64 bits. A site usually gets a /48 or /56 from its provider, which holds 65,536 or 256 LANs.

What is a wildcard mask?

The subnet mask turned inside out: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it to say which bits must match.

Which ranges can I use inside an office?

IPv4: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. IPv6: unique local addresses from fd00::/8, though most networks use the public prefix from their provider.